chore(auth): debounce refreshAuthTokens

packages/auth/src/providers/cognito/utils/refreshAuthTokens.ts

@@ -6,14 +6,15 @@ import { AuthConfig } from '@aws-amplify/core';
 import {
 	assertTokenProviderConfig,
 	decodeJWT,
+	deDupeAsyncFunction,
 } from '@aws-amplify/core/internals/utils';
 import { initiateAuth } from '../utils/clients/CognitoIdentityProvider';
 import { getRegion } from '../utils/clients/CognitoIdentityProvider/utils';
 import { assertAuthTokensWithRefreshToken } from '../utils/types';
 import { AuthError } from '../../../errors/AuthError';
 import { getUserContextData } from './userContextData';
 
-export const refreshAuthTokens: TokenRefresher = async ({
+const refreshAuthTokensFunction: TokenRefresher = async ({
 	tokens,
 	authConfig,
 	username,
@@ -72,3 +73,5 @@ export const refreshAuthTokens: TokenRefresher = async ({
 		username,
 	};
 };
+
+export const refreshAuthTokens = deDupeAsyncFunction(refreshAuthTokensFunction);

packages/aws-amplify/package.json

@@ -300,13 +300,13 @@
 			"name": "[Analytics] record (Kinesis)",
 			"path": "./dist/esm/analytics/kinesis/index.mjs",
 			"import": "{ record }",
-			"limit": "44.47 kB"
+			"limit": "44.48 kB"
 		},
 		{
 			"name": "[Analytics] record (Kinesis Firehose)",
 			"path": "./dist/esm/analytics/kinesis-firehose/index.mjs",
 			"import": "{ record }",
-			"limit": "41.50 kB"
+			"limit": "41.54 kB"
 		},
 		{
 			"name": "[Analytics] record (Personalize)",
@@ -384,7 +384,7 @@
 			"name": "[Auth] confirmSignIn (Cognito)",
 			"path": "./dist/esm/auth/index.mjs",
 			"import": "{ confirmSignIn }",
-			"limit": "25.89 kB"
+			"limit": "25.94 kB"
 		},
 		{
 			"name": "[Auth] updateMFAPreference (Cognito)",
@@ -396,19 +396,19 @@
 			"name": "[Auth] fetchMFAPreference (Cognito)",
 			"path": "./dist/esm/auth/index.mjs",
 			"import": "{ fetchMFAPreference }",
-			"limit": "8.30 kB"
+			"limit": "8.35 kB"
 		},
 		{
 			"name": "[Auth] verifyTOTPSetup (Cognito)",
 			"path": "./dist/esm/auth/index.mjs",
 			"import": "{ verifyTOTPSetup }",
-			"limit": "9.13 kB"
+			"limit": "9.18 kB"
 		},
 		{
 			"name": "[Auth] updatePassword (Cognito)",
 			"path": "./dist/esm/auth/index.mjs",
 			"import": "{ updatePassword }",
-			"limit": "9.14 kB"
+			"limit": "9.19 kB"
 		},
 		{
 			"name": "[Auth] setUpTOTP (Cognito)",
@@ -420,7 +420,7 @@
 			"name": "[Auth] updateUserAttributes (Cognito)",
 			"path": "./dist/esm/auth/index.mjs",
 			"import": "{ updateUserAttributes }",
-			"limit": "8.41 kB"
+			"limit": "8.46 kB"
 		},
 		{
 			"name": "[Auth] getCurrentUser (Cognito)",
@@ -432,7 +432,7 @@
 			"name": "[Auth] confirmUserAttribute (Cognito)",
 			"path": "./dist/esm/auth/index.mjs",
 			"import": "{ confirmUserAttribute }",
-			"limit": "9.15 kB"
+			"limit": "9.19 kB"
 		},
 		{
 			"name": "[Auth] signInWithRedirect (Cognito)",

packages/core/__tests__/utils/deDupeAsyncRequests.test.ts

@@ -0,0 +1,50 @@
+import { deDupeAsyncFunction } from '../../src/utils/deDupeAsyncFunction';
+
+describe('dedupeAsyncFunction()', () => {
+	const numberOfConcurrentCalls = 10;
+	const mockServiceFunction = jest.fn();
+	const mockReturnValue = { id: 1 };
+
+	beforeEach(() => {
+		mockServiceFunction.mockImplementation(async () => mockReturnValue);
+	});
+	afterEach(() => {
+		mockServiceFunction.mockClear();
+	});
+
+	it('should invoke the mockServiceFunction', async () => {
+		const deDupedFunction = deDupeAsyncFunction(mockServiceFunction);
+
+		deDupedFunction();
+		expect(mockServiceFunction).toHaveBeenCalledTimes(1);
+	});
+
+	it('should invoke the mockServiceFunction one time during concurrent sync calls', () => {
+		const deDupedFunction = deDupeAsyncFunction(mockServiceFunction);
+		for (let i = 0; i < numberOfConcurrentCalls; i++) {
+			deDupedFunction();
+		}
+		expect(mockServiceFunction).toHaveBeenCalledTimes(1);
+	});
+
+	it('should return a value once the mockServiceFunction is resolved', async () => {
+		const deDupedFunction = deDupeAsyncFunction(mockServiceFunction);
+		expect(await deDupedFunction()).toEqual(mockReturnValue);
+		expect(mockServiceFunction).toHaveBeenCalledTimes(1);
+	});
+
+	it('should allow to invoke the mockServiceFunction again after the promise has being resolved', async () => {
+		const deDupedFunction = deDupeAsyncFunction(mockServiceFunction);
+		for (let i = 0; i < numberOfConcurrentCalls; i++) {
+			expect(deDupedFunction()).toBeInstanceOf(Promise);
+		}
+
+		// resolves the promise
+		expect(await deDupedFunction()).toEqual(mockReturnValue);
+
+		// should allow to call the mockServiceFunction again
+		deDupedFunction();
+
+		expect(mockServiceFunction).toHaveBeenCalledTimes(2);
+	});
+});

packages/core/src/libraryUtils.ts

@@ -17,6 +17,7 @@ export {
 	retry,
 	urlSafeDecode,
 	urlSafeEncode,
+	deDupeAsyncFunction,
 } from './utils';
 export { parseAWSExports } from './parseAWSExports';
 export { LegacyConfig } from './singleton/types';

packages/core/src/singleton/apis/fetchAuthSession.ts

@@ -3,10 +3,8 @@
 
 import { fetchAuthSession as fetchAuthSessionInternal } from './internal/fetchAuthSession';
 import { Amplify } from '../Amplify';
-import { AuthSession, FetchAuthSessionOptions } from '../Auth/types';
+import { FetchAuthSessionOptions } from '../Auth/types';
 
-export const fetchAuthSession = (
-	options?: FetchAuthSessionOptions
-): Promise<AuthSession> => {
+export const fetchAuthSession = (options?: FetchAuthSessionOptions) => {
 	return fetchAuthSessionInternal(Amplify, options);
 };

packages/core/src/utils/deDupeAsyncFunction.ts

@@ -0,0 +1,38 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// this will make the tsc-compliance-test to pass
+type Awaited<T> = T extends null | undefined
+	? T // special case for `null | undefined` when not in `--strictNullChecks` mode
+	: T extends object & { then(onfulfilled: infer F, ...args: infer _): any } // `await` only unwraps object types with a callable `then`. Non-object types are not unwrapped
+	  ? F extends (value: infer V, ...args: infer _) => any // if the argument to `then` is callable, extracts the first argument
+			? Awaited<V> // recursively unwrap the value
+			: never // the argument to `then` was not callable
+	  : T; //
+/**
+ * returns in-flight promise if there is one
+ *
+ * @param callback - callback to be deduped.
+ * @returns - the return type of the callback
+ */
+export const deDupeAsyncFunction = <A extends any[], R>(
+	fun: (...args: A) => Promise<R>
+) => {
+	let inflightPromise: Promise<Awaited<R>> | undefined;
+	return async (...args: A): Promise<Awaited<R>> => {
+		if (inflightPromise) return inflightPromise;
+
+		inflightPromise = new Promise(async (resolve, reject) => {
+			try {
+				const result = await fun(...args);
+				resolve(result);
+			} catch (error) {
+				reject(error);
+			} finally {
+				inflightPromise = undefined;
+			}
+		});
+
+		return await inflightPromise;
+	};
+};

packages/core/src/utils/index.ts

@@ -15,3 +15,4 @@ export {
 export { urlSafeDecode } from './urlSafeDecode';
 export { urlSafeEncode } from './urlSafeEncode';
 export { deepFreeze } from './deepFreeze';
+export { deDupeAsyncFunction } from './deDupeAsyncFunction';

packages/datastore/src/sync/processors/subscription.ts

@@ -279,7 +279,7 @@ class SubscriptionProcessor {
 
 				try {
 					// retrieving current token info from Cognito UserPools
-					const session = await await fetchAuthSession();
+					const session = await fetchAuthSession();
 					oidcTokenPayload = session.tokens?.idToken?.payload;
 				} catch (err) {
 					// best effort to get jwt from Cognito